The great leaders were so many - Ibn Yunus, Ibn al-Haitham, Al-Biruni, Ibn Sina, Ali ibn Isa, al-Karkhi, Ibn Gabirol (all Muslim except the last, who was Jewish) - that, for a moment at least, the historian is bewildered. Yet, however distinguished all of those men, and many others who will be named presently, two stand out head and shoulders above the others: al-Biruni and Ibn Sina (Avicenna). It was chiefly because all of them that this period was one of such excellence and distinction. These two men, who by the way, knew one another, were extremely different. Al-Biruni represents the more adventurous and critical spirit, Ibn Sina the synthetic spirit, al-Biruni was more of a discoverer, and in that respect he came nearer to the modern scientific ideal; Ibn Sina was essentially an organizer, an encyclopedist, a philosopher. Both, even the latter, were primarily men of science, and it would be difficult to choose between them but the accidental fact that al-Biruni's life covered more fully the present period and thus may be said to represent it more completely. Ibn Sina was only 20 at the beginning of the century, and his life was ultimately cut short in 1037. Al-Biruni's first important work appeared about 1000 and he lived until 1048. Thus his time of activity and the first half of the eleventh century are not identical periods, and we are fully justified (more fully so than in almost every short case) in calling it the Time of al-Biruni.
Contemporary accounts
of Muslim achievements must be started with Ibn al-Haitham, who flourished
in Cairo at the beginning of the century. He was not only the greatest
Muslim physicist, but by all means the greatest of mediaeval times. His
researches on geometrical and physiological optics were the most significant
to occur between ancient times and the sixteenth century. His description
of the eye and his explanation of vision were distinct improvements. Muslim
scientists had developed a great interest in the determination of specific
gravity. Al-Biruni continued that tradition and measured the density of
18 precious stones and metals with remarkable accuracy. He observed that
the speed of light is incomparably greater than the of sound. Ibn Sina
investigated all the fundamental questions of physics which could be formulated
finite. His study of music was especially important and far ahead of the
contemporary Latin work. He described the doubling with octave, the fourth
and the fifth, and even with the third.
A college of Ibn al-Haitham in the Cairo academy, Masawaih al-Mardini,
explained the preparation empyreumatic oils. Ibn Sina intertained original
views on chemistry; he did not share the common belief of Muslim alchemists
that the coloring or bronzing of metals affected their substance, he thought
that the differences between metals were to deep to permit their transmutation.
An important alchemical treatise was composed in 1034 by al-Kathi.
Spain: Al-Karmani has already been mentioned. He was at once a mathematician and a surgeon. Ibn al-Wafid composed a treatise on simple drugs, which is partly extant in Latin, and a treatise on Balneography. To these two Muslims may be added the Jew, Ibn Janah, who flourished in Saragossa and wrote there in Arabic, a book on simple remedies.
Egypt: Not less than four great Physician enjoyed the patronage of the Fatimid rulers of Egypt. Masawaih al-Mardini (Mesue the Younger) compiled a large dispensatory which was immensely popular in mediaeval Europe. For centuries it remained the standard work on the subject. Ammar was perhaps the most original oculist of Islam, but his work was superseded by that of the Eastern contemporary, Ali ibn Isa. The surgical part of Ammar's ophthalmologic treatise is particularly important. The third of these physicians, Ibn al-Haitham (Alhazen) has already been dealt with many times; he must be remembered her because of his studies in physiological optics. Ali ibn Ridwan wrote various commentaries on Greek medicine, of which the best known was one on Galen's Ars prava; he also wrote a treatise on hygiene with special reference to Egypt. It should be noted that Masawaih was a monophysite Christian; the others were Muslims.
East: The
greatest physician of the time and one of the greatest of all times was
Ibn Sina (Avicenna). His enormous medical encyclopedia, the Qanun (Canon),
remained the supreme authority, not simply in Islam but also in Christendom,
for some six centuries. It contained a number of original observations,
but its hold on the people was chiefly due to its systematic arrangement
and its very dogmatism. Ibn Sina was not as great a physician as Galen,
but he had very much the same intellectual qualities and defects and his
ascendancy was largely based upon the same grounds. He had the advantage
over Galen being able to take into account the vast experience of Muslim
physicians.
Ibn al-Taiyib wrote commentaries on Greek medicine. Abu Sa'id Ubaid
Allah, of the famous Bakhtyashu family, wrote treatise on love-sickness
and discussed the philosophical terms used by physicians. Ibn Butlan compiled
the so-called Tables of Health, a medical summary, divided into 15 vertical
columns; he is perhaps the originator of that typical form of synopsis.
Finally Ali ibn Isa (Jesu Haly) was the author of the most famous ophthalmologistical
treatise written in Arabic, it is very remarkable that not than three of
these physicians, that is more than half of them, were Christians living
in Bagdad: Ibn al-Taiyib, Abu Sa'id Ubaid Allah, and Ibn Butlan. This testifies
for the faithfulness of the Christian community of Bagdad and the toleration
of the Muslim rulers. It should be added that the other physicians, i.e., the Muslims, were far more important.
IBN AL-SAMH
Abu al-Qasim Asbagh
ibn Mohammed ibn al-Samh. Flourished at Granada; died May 29, 1035, at
the age of 56. Hispano-Muslim mathematician and astronomer. He wrote treatises
on commercial arithmetic (al-mu'amalat), on two mental calculus (hisab
al-hawa'i), on the nature of numbers, two on geometry, two on astrolabe,
its use and construction. His main work seems to have been the compilation
of astronomical tables, according to the Siddhanta method (for which see
my notes on Mohammed ibn Ibrahim al-Fazari second half of eighth century),
together with theoretical explanations (c. 1025).
H. Suter: Mathematiker (85,
1900; 168, 1902).
IBN ABI-L-RIJAL
In Latin, Abenragel
(also Albohazen, Alboacen, which was more correct, for Abenragel was his
father's name, rather than his own). Abu-l-Hasan Ali ibn Abi-l-Rijal al-Saibani
al-Katib al-Maghribi. Born in Cordova or else where in Spain or in northern
Africa, flourished in Tunis some time about 1016 to 1040, died after 1040.
Muslim astrologer. His main work is the "distinguished book on horoscopes
from the constellations" (al-bari fi ahkam al-nujum). It was translated
by Judah ben Moses from Arabic into Castilian, then from Castilian into
Latin by Aegidius de Tebaldis and Petrus de Regio. He wrote a physiognomic
treatise on Naevi.
H. Suter: Die Mathematiker
und Astronomen der Araber (100, 1900; Nachtrage, 172, 1902); encyclopedia
of Islam (vol. 2, 356, 1916).
IBN AL-SAFFAR
Abu-l-Qasim Ahmed
ibn Abdallah ibn Omar al-Ghafiqi, best known under the name of Ibn al-Saffar,
meaning son of coppersmith. Flourished at Cordova, toward the end of his
life he retired in Denia and died there in 1035. Hispano-Muslim mathematician
and astronomer. He wrote a treatise on the astrolabe and compiled tables
according to the Siddhanta method.
H. Suter: Mathematiker (86,
225, 1900; 169, 1902).
IBN YUNUS
Abu Hasan Ali ibn
abi Sa'id Abd al-Rahman ibn Ahmed ibn Yunus (or Ibn Yunus) al-Sadafi al-Misri.
Died in Cairo, 1009 (not 1008). The date of his birth is unknown, but his
father died in 958-59. Perhaps the greatest Muslim astronomer. A well equipped
observatory in Cairo enabled him to prepare improved astronomical tables.
Begun c. 990 by order of the Fatimid caliph al-Aziz (975-996), they were
completed in 1007 under the latter's son al-Hakim (996-1020) and are called
after him the Hakemite Tables (al-zij al-kabir al-Hakimi). They contain
observations of eclipses and conjunctions, old and new, improved values
of astronomical constants (inclination of the ecliptic, 23o
35`; longitude of the sun's apogee, 86o
10`; solar parallax reduced from 3` to 2`; precession, 51.2``
a year, no allusion to trepidation) and accounts of the geodetic measurements
carried on order by al-Ma'mun (q. v., first half of ninth century.)
His contributions to trigonometry, though less important than those
of Abu-l-Wafa; are considerable. He solved many problems of spherical astronomy
by means of orthogonal projections. He introduced the first of those prosthapheretical
formulae which were indispensable before the invention of the logarithms,
namely, the equivalent of
IBN AL-HAITHAM
See notes in the physical section,
below.
KUSHYAR IBN LABBAN
Abu-l-Hasan Kushayr
ibn Labban ibn Bashahri al-Jili (i. e., from Jilan, south of the Caspian
Sea). Flourished c. 971-1029; his main work was probably done about
the beginning of the eleventh century. Persian mathematician and astronomer,
writing in Arabic. He seems to have taken an important part in the elaboration
of trigonometry. For example, he continued the investigations of Abu-l-Wafa,
the devoted much space to this in his tables, al-zij al-jami wa-l-baligh
(the comprehensive and mature tables), which were translated into Persian
before the end of the century. He wrote also an astrological introduction
and an arithmetic treatise (extant to Hebrew).
H. Suter: Mathematiker und
Astronomen der Araber (83, 235, 1900; 168, 1902).
IBN AL-HUSAIN
Abu Ja'far Mohammed
ibn al-Husain. Flourished not long after al-Khujandi (q. v., second half
of the tenth century). Mathematician. He wrote a memoir on rational right
angled triangles and another on the determination of two mean proportionals
between two lines by a geometrical method (vs. kinematic method), i. e.,
by the use of what the Muslims called "fixed geometry", al-handasa al-thabit.
Solution of the equation
ABU-L-JUD
Abu-l-Jud Mohammed
ibn al-Lith, contemporary of al-Biruni. Mathematician. Solution of al-Birunic
problems by means of intersecting conics. Regular heptagon and enneagon.
Classification of equations and their reduction to conic sections.
Suter: Die Mathematiker und
Astronomen der Araber (79, 1900).
AL-KARKHI
Abu Bakr Mohammed
ibn al-Hassan (or Husain) al-Hasib (the calculator) al-Karkhi, meaning
of Karkh, a suburb of Bagdad. Flourished in Bagdad during the vizierate
of Abu Ghakib Mohammed ibn Khalaf Fakhr al-mulk (glory of the realm), who
died in 1016; he died himself c. 1019 to 1029. One of the greatest Muslim
mathematicians. His book on arithmetic (the sufficient on calculation,
alkafi fi-l-hisab) is based chiefly of the Greek and Hellenistic knowledge.
No numerals of any kind are used, the names of the numbers being written
in full. Casting out of the nines and elevens.
AL-NASAWI
Abu-l-Hasan Ali ibn
Ahmed al-Nasawi. From Nasa, Khurasan. Flourished under the Buwayhid sultan
Majd al-dawla, who died in 1029-30, and under his successor. Persian mathematician.
He wrote a practical arithmetic in Persian, before 1030, and later under
Majd al-dawla's successor an Arabic translation of it, entitled the "Satisfying
(or Convincing) on Hindu Calculation" (al-muqni fi-l-hisab al hindi). He
also wrote on Archemedes's lemnata and Menelaos's theorem (Kitab al-ishba,
satiation). His arithmetic explains the division of fractions and the extraction
of square and cubic roots (square root of 57,342; cubic root of 3, 652,
296) almost in the modern manner. It is remarkable that al-Nasawi replaces
sexagesimal by decimal fractions, e. g.,
Suter: Die Mathematiker und
Astronomen der Araber (96, 1900) Uber das Rechenbuch des Ali ben Ahmed
el-Nasawi (Bibliotheca Mathematica, vol. 7, 113-119, 1906).
IBN AL-HAITHAM
Latin name: Alhazen.
Abu Ali al-Hasan ibn al-Hasan (or al-Husain) ibn al-Haitham. Born c. 965
in Basra, flourished in egypt under al-Hakim (996 to 10200 died in Cairo
in 1039 or soon after. The greatest Muslim physicist and one of the greatest
students of optics of all the times. He was also an astronomer, a mathematician,
a physician, and he wrote commentaries on Aristotle and Galen.
The Latin translation of his main work, the Optics (kitab al-manazir),
exerted a great influence upon Western science (R. Bacon; Kepler). It showed
a great progress in the experimental method. Research in catoptrics: spherical
and parabolic mirrors, spherical aberration; in dioptrics: the ratio between
the angle and incidence and refraction does not remain constant; magnifying
power of a lens. study of atmospheric refraction. The twilight only ceases
or begins when the sun is 19o below the horizon; attempt to
measure the height of the atmosphere on that basis. Better description
of the eye, and better understanding of vision, though ibn al-haitham considered
the lens as the sensitive part; the rays originate in the object seen,
not in the eye. Attempt to explain binocular vision. Correct explanation
of the apparent increase in the size the sun and the moon when near the
horizon. earliest use of the camera obscura.
The catoptrics contain the following problem, known as Alhazen's
problem: from two points of the plane of a circle to draw lines meeting
at point of the circumference and making equal angles with the normal at
that point. It leads to an equation of the fourth degree. Alhazen solved
it by the aid of an hyberpola intersecting a circle. He also solved the
so-called al-Mahani's (cubic) equation (q. v., second half of the ninth
century) in a similar (Archimedian) manner.
Suter: Die Mathematiker und
Astronomen der Araber (91-95, Nachtrage, 169, 1902).
AL-KATHI
Abu-l-Hakim Mohammed
ibn Abd al-Malik al-Salihi al-Khwarizmi al-Kathi. Flourished in Bagdad
c. 1034. Muslim Chemist, he wrote, in 1034, a treatise on alchemy entitled
"Essence of the Art and Aid to the Workers" (Ain al-san'a wa awn-al-sana'a),
strikingly similar in some respects to the "Summa perfectionis magisterii"
of the Latin Geber (for which see my notes on Jabir, second half of eighth
century).
H. E. Stapleton and R. F.
Azo: Alchemical Equipments in the Eleventh century (Memories of Asiatic
Society of Bengal, vol. 1, 47-70, 1 pl., Calcutta, 1905. Containing Arabic
text, an analysis of it, and an introduction; very important).
IBN AL-WAFID
Latin name: Abenguefit.
Abu-l- Mutarrif abd al-Rahman ibn Mohammed ibn Abd al-Karim ibn Yahya ibn
al-Wafid al-Lakhmi. From Toledo, where he flourished; born 997, died c.
1074. Hispano-Muslim physician, Pharmacologist. His main work, on simple
drugs (Kitab al-adwaiya al-mufrada), based on Galen and Discorides and
also on personal investigations, is partly extant in a Latin translation.
He preferred to use dietetic measures, and, if drugs were needed, to use
the simplest ones. He advised a method of investigating the action of the
drugs. He also wrote a balneotherapy.
C. Brocklmann: Arabischen
Litteratur (vol. 1, 485, 1898. Two Arabic manuscripts mentioned).
AMMAR
Latin name: Canamusali.
Abu-l-Qasim Ammar ibn Ali al-Mawsili. From Mawsil in Iraq; flourished in
Egypt in the reign of al-Hakim, who ruled from 996-1020. Physician. The
most original of Muslim oculists, His work was eclipsed by that of his
contemporary Ali ibn Isa, which was more comprehensive. His summary on
the treatment of the eye (Kitab al-muntakhab fi ilaz al-ain) contains many
clear descriptions of diseases and treatments, arranged in logical order.
The surgical part is especially important.
E. Mittwoch: Encyclopaedia
of Islam (vol. 1, 332, 1910).
IBN AL-HAITHAM
See notes in physical section, above.
ALI IBN RIDWAN
Abu-l-Hasan Ali ibn
Radwan ibn Ali ibn Ja'far al-Misri. Born in Jiza near Cairo, c. 998. Flourished
in Cairo and died there in 1061 or in 1067. Astrologer. physician. The
author of many medical writings of which the most popular was his commentary
on Galen'a Ars prava, which was translated by Gerardo Cremonese. I may
still quote his treatise on hygiene with special reference to Egypt (fi
daf mudar al-abdan bi-ard Misr). He wrote various other commentaries on
Hippoctates and Galen and on Ptolemy's astrological books.
C. Brocklmann: Arabischen
Litteratur (vol. 1, 484, 1898).
IBN SINA
Abu Ali al-Hassan
ibn Abdallah ibn Sina. Hebrew, Aven Sina; Latin, Avicenna. Born in 980
at Afshana, near Bukhara, died in Hamadhan, 1037. Encyclopaedist, philosopher,
physician, mathematician, astronomer. The most famous scientist of Islam
and one of the most famous of all races, places, and times; one may say
that his thought represents the climax of mediaeval philosophy. He wrote
a many great treatises in prose and verse; most of them in Arabic, a few
in Persian. His philosophical encyclopedia (Kitab al-shifa, sanatio) implies
the following classification: theoretical knowledge (subdivided, with regard
to increasing abstraction, into physics, mathematics, and metaphysics),
practical knowledge (ethics, economy, politics). His philosophy roughly
represents the Aristotelian tradition as modified by Neoplatonic influences
and Muslim theology. Among his many other philosophical works, I must still
quote a treatise on logic, Kitab al-isharat wal-tanbihat (The Book of Signs
and Adonitions). As ibn Sina expressed his views on almost any subject
very clearly, very forcible, and generally more than once, his thought
is, or at any rate can be, known with great accuracy.
His most important medical works are the Qanun (Canon) and a treatise
on cardiac drugs (hitherto unpublished). The Qanun fi-l-tibb is an immense
encyclopedia of medicine (of about a million words), a codification of
the whole ancient and Muslim knowledge. Being similar in many respects
to Galen, Ibn Sina elaborated to a degree the Galenic classifications (for
example, he distinguished 15 qualities of pain). Because of its formal
perfection as well as its intrinsic value, the Qanun superseded Razi's
Hawi, Ali ibn Abbas's Maliki, and even works of Galen, and remained supreme
for six centuries. However the very success of Ibn Sina as an encyclopedist
caused his original observations to be correspondingly depreciated. Yet
the Qanun contains many examples of good observation - distinction of mediastinitis
from pleurisy; contagious nature of phthitis; distribution of diseases
by soil and water; careful description of skin troubles, of sexual diseases;
and supervisions; of nervous ailments (including love sickness); many psychological
and pathological facts clearly analyzed if badly explained.
Ibn Sina's interest in mathematics was philosophical rather than
technical and such as we would expect in a late Neoplatonist. He explained
the casting out of nines and its application to the verification of square
and cubes. Many of his writings were devoted to mathematical and astronomical
subjects. He composed a translation on Euclid. He made astronomical observations,
and devised a contrivance the purpose of which was similar to that of the
vernier, that is, to increase the precision of instrumental readings.
He made a profound study of various physical questions - motion,
contact, force, vacuum, infinity, light, and heat. He observed that if
the perception of light is due to the emission of some sort of particles
by the luminous source, and speed of light must be finite. He made investigations
on specific gravity.
He did not believe the possibility of chemical transmutation, because
in his opinion the differences of the metals were not superficial, but
much deeper; coloring or bronzing the metals does not affect their essence.
It should be noted that these views were radically opposed to those which
were then generally accepted.
Ibn Sina's treatise on minerals was the main source of the geological
ideas of the Christian encyclopedist of the thirteenth century.
Ibn Sina wrote an autobiography which was completed by his favorite
disciple al-Juzajani.
His triumph was too complete; it discouraged original investigations
and sterilized intellectual life. Like Aristotle and Vergil, Avicenna was
considered by the people of later times as a magician.
C. Brocklmann: Geschichte
der arabischen Litteratur (vol. 1, 452-458, 1898. With list of 99 works).
IBN AL-TAIYIB
Abu-l-Faraj Abdallah
Ibn al-Taiyib al-Iraqi. Latin name : Abulpharagius Abdalla Benattibus.
Died in 1043-44. Nestorian physician. Secertary to Elias I, Nestorian Catholics
from 1028 to 1049. Physician at the Adudite hospital in Bagdad. He had
many commentaries on Greek medicine, and original memories on various medical
topics, also a translation of the pseudo-Aristotelian De plantis, with
additional excerpts from ancient literature.
From Arabic translation of the Diatessaron ascribed to him.
Brocklmann: Arabischen Litteratur
(vol. 1, 482, 1898).
ABU SA'ID UBAID ALLAH
Abu Sa'id Ubaid Allah
ibn Bakhtyashu. Flourished in Maiya-fariqin, Jazirah; friend of Ibn Butlan;
died in 1058. Physician. The last and possibly the greatest representative
of the Bukhtyashu, a syrian family of physicians which emigrated from Junsishapur
to Bagdad in 765. His main works are the Reminder of the Homestayer, dealing
with the philosophical terms used in medicine, and a treatise on lovesickness.
C. Brocklmann: Encyclopaedia
of Islam (t. 1, 601, 1911).
IBN BUTLAN
Abu-l-Hasan al-Mukhtar
ibn al-Hasan ibn Abdun ibn Sa'dun ibn Butlan. Latin name: Elluchasem Elimither.
Flourished in Bagdad; died, probably in Antioch, in or soon after 1063.
Christian physician. He wrote synoptic tables of hygiene, dietetics, domestic
medicine, called the Tables of Health. He probably originated that form
of synopsis, which was developed by ibn Jazla (q. v., second half of eleventh
century). Medical polemic with Ali ibn Ridwan.
C. Brocklmann: Arabischen
Litteratur (vol. 1, 483, 1898).
ALI IBN ISA
Ali ibn Isa or Jesu
Haly. flourished in Bagdad in the first half of the eleventh century. He
is said to have been a christian. The most Famous Arabic oculist. His "Manual"
in three books, Tadhkirat al-kahhalin, is the oldest Arabic work on ophthalmology
of which the original text is completely extant. It is based partly on
ancient knowledge, partly on personal experience. It is at once very detailed
and very comprehensive. The first book deals with the anatomy and physiology
of the eye; the second with the diseases externally visible; the third
with hidden diseases, dietetics, and general medicine from the oculistic
standpoint; 130 eye diseases are carefully described; 143 drugs characterized.
J. Hirschberg: Die arabischen
Lehrbucher der Augenheilkunde (Abhd. der preuss. Ak. der Wiss., 117 p.,
Berlin, 1905).